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  Vacuum evacuation device and method, and substrate processing apparatus and methodUSPTO Application #: 20070048145Title: Vacuum evacuation device and method, and substrate processing apparatus and method Abstract: A vacuum evacuation device 2 of the invention comprises a vacuum pump 4,5 for exhausting a gas G2 in a process chamber 21 into which a process gas G1 is introduced and in which a process reaction is performed, to form a vacuum in said process chamber 21; and a control means 6 for performing a first control that regulates the rotational speed of said vacuum pump 4,5 such that a pressure condition in said process chamber 21 reaches a pressure condition suitable for said process reaction during said process reaction, wherein said control means 6 calculates a specified rotational speed for said vacuum pump 4,5 based on process information related to said process reaction, and performs a second control that brings said vacuum pump 4,5 to said specified rotational speed before said first control. The vacuum evacuation device 2 is capable of bringing the pressure in a process chamber 21 to the target pressure in a short period without a vacuum pump 4,5 being overloaded, regardless of the process reaction condition. (end of abstract) Agent: Wenderoth, Lind & Ponack, L.L.P. - Washington, DC, US Inventors: Katsutoshi Ishii, Ken Nakao, Takanobu Asano, Kota Umezawa, Hiroaki Ogamino, Tadashi Urata, Katsuaki Usui, Masafumi Inoue, Shinichi Sekiguchi, Hironobu Yamasaki USPTO Applicaton #: 20070048145 - Class: 417044200 (USPTO) Related Patent Categories: Pumps, Condition Responsive Control Of Pump Drive Motor, By Control Of Electric Or Magnetic Drive Motor, Responsive To Pump Fluid Pressure The Patent Description & Claims data below is from USPTO Patent Application 20070048145. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] 1. Technical Field [0002] The present invention relates to a vacuum evacuation device and method for regulating the rotational speed of a vacuum pump for exhausting a gas from a process chamber to control the pressure condition in the process chamber, and a substrate processing apparatus for evacuating a process chamber using the vacuum evacuation device to process a substrate in the process chamber and a substrate processing method for evacuating a Process chamber using the vacuum evacuation method to process a substrate in the process chamber. [0003] 2. Related Art [0004] As shown in FIG. 21, a conventional vacuum evacuation device 102 includes a turbo molecular pump 104 for exhausting a gas G2 from a process chamber 121 into which a process gas G1 is introduced at a flow rate regulated by a flow rate regulator 103, a dry pump 105 for exhausting the gas G2 from the exhaust side of the turbo molecular pump 104, and a pressure controller 106 for regulating the rotational speed of the turbo molecular pump 104 to control the pressure in the process chamber 121. The turbo molecular pump 104 incorporates a turbo molecular pump motor 104M, and the dry pump 105 incorporates a dry pump motor 105M. [0005] The vacuum evacuation device 102 also includes a pressure gauge 107 for measuring the pressure in the process chamber 121, a pressure gauge 108 for measuring the pressure on the exhaust side of the turbo molecular pump 104, an electromagnetic valve 109 installed between the turbo molecular pump 104 and the dry pump 105 to prevent the pressure from being abruptly released to atmospheric pressure when the dry pump 105 is stopped, a motor control panel 110 for receiving external power E1 and supplying motor power E2 to the turbo molecular pump motor 104M, and a motor control panel 111 for receiving external power E1 and supplying motor power E3 to the dry pump motor 105M. [0006] The pressure gauges 107 and 108 send a pressure signal indicating the measured pressure to the pressure controller 106. The pressure controller 106 sends to the motor control panel 110 a rotational speed command signal i6 to command the rotational speed of the turbo molecular pump 104, and the motor control panel 110 sends to the turbo molecular pump motor 104M power E2 regulated so as to achieve the commanded rotational speed. The pressure controller 106 receives from a process controller (not shown) a pressure control start signal i1 to start pressure control in the process chamber 121. [0007] Next, with reference to FIG. 22 and FIG. 21, the steps of an operation method for the vacuum evacuation device 102 are described to perform conventional control of the pressure in the process chamber 121 by regulating the rotational speed of the turbo molecular pump 104. When the turbo molecular pump 104 and the dry pump 105 are respectively operated at the rated rotational speed (step S101), the process gas G1 is introduced into the process chamber 121 (step S102), and the process controller (not shown) sends a pressure control start signal i1 to the pressure controller 106 (step S103). Then, control of the pressure in the process chamber 121 is started by regulating the speed of the turbo molecular pump 104 (step S104), and the pressure in the process chamber 121 reaches the target value (step S105). After that, the process controller (not shown) sends a pressure control stop signal (not shown) to the pressure controller 106 (step S106), and the pressure control in the process chamber 121 is terminated. [0008] Now, with reference to FIG. 23 and FIG. 21, the conventional pressure control is described in view of the passage of time. In the drawing, the horizontal axis represents time, and the vertical axis represents pressure or rotational speed. Also in the drawing, the line P102 represents the pressure in the process chamber 121, the line N104 the rotational speed of the turbo molecular pump 104, and the line N105 the rotational speed of the dry pump 105. Before time t101, at which introduction of the process gas G1 introduced into the process chamber 121 is started, the turbo molecular pump 104 and the dry pump 105 are respectively driven at the rated speed and the process chamber 121 is under the rated pressure (a vacuum). [0009] At time t101, introduction of the process gas G1 into the process chamber 121 is started, and the pressure in the process chamber 121 starts increasing. At time t102, a pressure control start signal i1 is input to the pressure controller 106 to start pressure control. Since the target pressure is higher than the rated pressure, the pressure controller 106 performs speed regulation that decreases the speed of the turbo molecular pump 104. The speed of the dry pump 105 is not regulated but kept at the rated speed. As the speed of the turbo molecular pump 104 decreases, the pressure in the process chamber 121 increases. The pressure in the process chamber 121 is fed back from the pressure gauge 107 to the pressure controller 106, which based on that pressure performs feedback control so as to increase and decrease the speed of the turbo molecular pump 104. At time t103, the pressure in the process chamber 121 reaches the target value and is kept at the value. At time t104, the process Controller (not shown) sends a pressure control stop signal (not shown) to the pressure controller 106, and the pressure control in the process chamber 121 is terminated. [0010] In the conventional vacuum evacuation device, after a pressure control start signal to start pressure control in the process chamber is input to the pressure controller, the speed of the turbo molecular pump is regulated so as to bring the pressure in the process chamber to the target pressure. [0011] However, to prevent the pressure from overshooting during the pressure control in the process chamber, the pump speed is regulated so as to decrease from the rated speed. It is thus necessary to greatly change the pump speed until changes in the pump speed are reflected in changes in the pressure in the process chamber. [0012] Changes in the pressure in the process chamber are primarily governed by changes in the speed of the turbo molecular pump, though also influenced by the process condition. The period required for the pressure in the process chamber to reach the target pressure is approximately equal to the period required for the speed of the turbo molecular pump to change. [0013] However, in case of using a turbo molecular pump including a magnetic bearing which operates in a vacuum in a non-contacting manner, for example, deceleration takes time due to the absence of friction which acts on the rotor. In addition, the pressure in the process chamber does not change linearly with the change in the rotational speed of the turbo molecular pump, and it is necessary to greatly change the rotational speed, which prolongs the control period to bring the pressure in the process chamber to the target pressure. Further, in the case where a process condition exceeding the evacuation capacity of the turbo molecular pump is given while cleaning the process chamber or the like, increase in the motor power consumption and a loss of synchronization may be caused due to overload operation. Rotor runout may also be caused, which could result in the rotor contacting with the protective bearing. [0014] In view of the foregoing, it is therefore an object of the present invention to provide a vacuum evacuation device and method capable of bringing the pressure in a process chamber to the target pressure in a short period without a vacuum pump being overloaded, regardless of the process reaction condition, and to provide a substrate processing apparatus using the vacuum evacuation device and a substrate processing method using the vacuum evacuation method. SUMMARY OF THE INVENTION [0015] For the purpose of accomplishing the above object, a vacuum evacuation device 2 of the invention comprises a vacuum pump 4,5 for exhausting a gas G2 in a process chamber 21 into which a process gas G1 is introduced and in which a process reaction is performed, to form a vacuum in said process chamber 21; and a control means 6 for performing a first control that regulates the rotational speed of said vacuum pump 4,5 such that a pressure condition in said process chamber 21 reaches a pressure condition suitable for said process reaction during said process reaction, wherein said control means 6 calculates a specified rotational speed for said vacuum pump 4,5 based on process information related to said process reaction, and performs a second control that brings said vacuum pump 4,5 to said specified rotational speed before said first control, as shown in FIG. 1 for example. [0016] With this construction, a specified rotational speed for the vacuum pump is calculated based on process information related to process reaction, and the vacuum pump can be brought to the specified speed suitable for the process reaction before the first control. Therefore, it is possible to bring the process chamber to a pressure condition suitable for the process reaction in a short period without the vacuum pump being overloaded in the first control, regardless of the process reaction condition. [0017] The phrase "bringing to a pressure condition" refers to, for example, bringing to a certain pressure value, bringing to and keeping at a certain pressure value, changing the pressure at a constant pressure increase or reduction rate, including a pressure condition where the pressure is changed at a constant pressure increase or reduction rate, changing the pressure regularly in terms of time, and changing the pressure increase or reduction rate regularly in terms of time. [0018] It is typically necessary to increase the pressure in the process chamber in order to create a pressure condition suitable for process reaction, and thus the vacuum pump is decelerated to a specified rotational speed. [0019] For the purpose of accomplishing the above object, a vacuum evacuation device 2 of the invention may comprise a first vacuum pump 4 for exhausting a gas G2 in a process chamber 21 into which a process gas G1 is introduced and in which a process reaction is performed, to form a vacuum in said process chamber 21; a second vacuum pump 5 connected to the exhaust side of said first vacuum pump 4 to exhaust a gas G2 from said exhaust side to form a vacuum in said process chamber 21; and a control means 6 for performing a first control that regulates the rotational speed of one of said first vacuum pump 4 and said second vacuum pump 5 such that a pressure condition in said process chamber 21 reaches a pressure condition suitable for said process reaction during said process reaction, wherein said control means 6 calculates a specified rotational speed for said one vacuum pump 4 or 5 based on process information related to said process reaction, and performs a second control that brings said one vacuum pump 4 or 5 to said specified rotational speed before said first control, as shown in FIG. 1 for example. [0020] With this construction, a specified rotational speed for one of the first vacuum pump and the second vacuum pump is calculated based on process information related to process reaction, and the one vacuum pump can be brought to the specified speed suitable for the process reaction before the first control. Therefore, it is possible to bring the process chamber to a pressure condition suitable for the process reaction in a short period without the vacuum pump being overloaded in the first control, regardless of the process reaction condition. [0021] For the purpose of accomplishing the above object, a vacuum evacuation device 2 of the invention may comprise a first vacuum pump 4 for exhausting a gas G2 in a process chamber 21 into which a process gas 21 is introduced and in which a process reaction is performed, to form a vacuum in said process chamber 21; a second vacuum pump 5 connected to the exhaust side of said first vacuum pump 4 to exhaust a gas G2 from said exhaust side to form a vacuum in said process chamber 21; and a control means 6 for performing a first control that regulates the rotational speed of said first vacuum pump 4 such that a pressure condition in said process chamber 21 reaches a pressure condition suitable for said process reaction during said process reaction, and regulates the rotational speed of said second vacuum pump 5 such that a pressure condition on said exhaust side reaches a specified pressure during said process reaction, wherein said control means calculates a specified rotational speed for at least one of said first vacuum pump 4 and said second vacuum pump 5 based on process information related to said process reaction, and performs a second control that brings said at least one vacuum pump 4 or 5 to said specified rotational speed before said first control as shown in FIG. 1 for example. [0022] With this construction, a specified rotational speed for at least one of the first vacuum pump and the second vacuum pump is calculated based on process information related to process reaction, and the at least one vacuum pump can be brought to the specified speed suitable for the process reaction before the first control. Therefore, it is possible to bring the process chamber to a pressure condition suitable for the process reaction in a short period without the vacuum pump being overloaded in the first control, regardless of the process reaction condition. The control means may calculate respective specified rotational speeds for the first vacuum pump and the second vacuum pump based on process information related to the process reaction, and may perform a second control that brings the first vacuum pump and the second vacuum pump to the respective specified rotational speeds before the first control. In this way, it is possible to appropriately perform control over a wider pressure range and control involving pressure changes with a high pressure change rate. Continue reading... Full patent description for Vacuum evacuation device and method, and substrate processing apparatus and method Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Vacuum evacuation device and method, and substrate processing apparatus and method patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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